Herbert

Herbert Inlet

Characteristics

View oriented towards the head of Herbert Inlet

Herbert Inlet is located in North-west portion of Clayoquot Sound. Glacial activity formed Herbert Inlet by carving steep valleys that drop into the inlet and a deep, wide fjord. The glacial activity is what created the deep basin and shallow sill of Herbert Inlet. The depth of Herbert Inlet is around 140 to 160 meters deep with an 5-meter sill. The sill in this inlet is the most shallow of all of the inlets in Clayoquot Sound. Herbert inlet runs 1.1 nautical miles in width and 12.5 nautical miles in length. Located at the mouth of Herbert inlet is McKay Island and just past the small island is the passsage, Miller Channel. At the head there are mant massive waterfalls and the Moyeha River. The Moyeha River is the major river feeding into Herbert Inlet. The river is 11 kilometers long and 32 meters wide with many small rivers leading into it that ultimately discharge into Herbert Inlet. Located in Herbert inlet there is Quait Bay, a deep cove often visited for outdoor recreation, and Strathcona Provincial Park, the largest park on Vancouver Island. Currently, there is still some helicopter logging that takes place at the mouth of Herbert Inlet. Although helicopter logging does less damage to the land when compared to traditional logging, there are still negative impacts when removing the old growth trees from Clayoquot Sound. Also located in Herbert Inlet, near the mouth, there are salmon fish farm. There are also fish farms located in Millar Channel and near the islands near the mouth of the inlet.

Tracie Barry at the waterfall located at the head of the inlet

View from Herbert Inlet facing towards Millar Channel

Sampling Conditions

Map of locations of data stations, Herbert Inlet stations are 31-38

Meteorological Conditions During Inlet Sampling

Data was used from Tofino Airport provided by the Government of Canada website

September 10th

September 11th

Tidal Pattern During Sampling Period

Data was used from Riley Cove provided by Sailwx, a website.

Nutrient Choropleth Maps

NO₃Levels at Surface, Chlorophyll Max (CMAX), and Bottom

Image carousel with nitrate levels at surface, chlorophyll max, and bottom

Surface NO₃ levels are depleted likely from the lack of ocean water intrusion. There is a slight increase in NO3 at the head.

CMax NO₃ levels are lowest in the middle with larger blooms at the head a mouth where there is slight water intrusion.

Bottom NO₃ levels are highest at the bottom which is a common theme across inlets. The NO3 levels are fairly consistant throughout.

PO₄ Levels at Surface, Chlorophyll Max (CMAX), and Bottom

Image carousel with phosphate levels at surface, chlorophyll max, and bottom

Surface PO₄ levels are depleted, likely from the lack lack of ocean water intrusion. Levels of PO4 remain fairly steady throughout the inlet.

CMax PO₄ levels are lowest in the middle with a mild increase near the head and mouth

Bottom PO₄ levels are highest at the bottom caused from phystoplankton dying and sinking to the bottom and holding the nutrients there due to the lack of upwelling

Si(OH)4 Levels at Surface, Chlorophyll Max (CMAX), and Bottom

Image carousel with silicate levels at surface, chlorophyll max, and bottom

Surface Si(OH)4 levels are depleted with a slight increase in levels near the head where the Moyeha River enters the inlet

CMax Si(OH)4 levels are lowest in the middle with a mild increase near the head and mouth.

Bottom Si(OH)4 levels follow the same pattern of the previous nutrient maps that show higher concentrations on the bottom.

Nutrient Trends

All three nutrient types mapped showed similar characteristics between their surface, chlorophyll max, and bottom and the nutrient quantities. It is expected that in Herbert inlet would have depleted nutrients at the top of the water due to phytoplankton using them. The deep water in this inlet consistently showed the water containing more nutrients due to phytoplankton dying off and sinking to the bottom where the nutrients can accumulate. In the nutrient maps, you can see similar trends with Shelter and Sydney inlets, but the pattern changes with Bedwell and Tofino inlets.

Contour Maps & Water Properties

Herbert Inlet is colder than some other inlets reaching 9 degrees at the bottom. Tofino Inlet is similar in depth but is warmer. This observed difference is likely caused from the shallow sill of Herbert that acts as a barrier to allow the ocean water to enter.

The salinity of Herbert reads at about 31 PSU, which is greater than Tofino’s, which, again, is likely due to the lack of sea water intrusion. The low temperature and high salinity of Herbert creates water that is denser compared to Tofino.

Herbert’s density is highly stratified. The surface layer shows salty water coming in around station 31, the mouth of the inlet, and fresh river water coming from the Moyeha River and the waterfall around station 38.

The dissolved oxygen in this inlet is very low, especially at the bottom, close to anoxic. Other inlets have higher oxygen levels because they lack the shallow sill the Herbert has that limits ocean water input.

Fluorescence in Herbert Inlet is low and near the mouth of the inlet. The sill continues to act as a barrier but when some tidal currents pick up and allows small amounts of oceanic water in and create a bloom near the sill.

Transmissivity is low and near the mouth of the inlet. The source of the transmissivity is from the fluorescence, which can be seen in a similar placement on the fluorescence contour map.

Image carousel for all contour maps to view larger images

Water Property Trends

The major control on all the parameters in Hebert is the shallow sill at the head of the inlet that doesn’t allow it to flush with ocean water as easily as other inlets. The shallow sill stops seawater intrusion thus making Herbert colder and more saline, and, therefore, denser. The contour maps show this relation between water temperature and salinity and their impact together on water density. The lack of flushing also leaves Herbert inlet with low amounts of dissolved oxygen deep in the inlet. Phytoplankton blooms near the mouth of the where mixing over the sill occurs making nutrients more available in the photic zone and increases the fluorescence and transmissivity in that area.

Page developed by Faith Dewitz

Page updated

Report abuse